What is a social group? why are social groups important in society? what are two groups that you are a part of?

So a social group is a group of people that share similar characteristics. And they are important because it gets you to interact with peers. The last question is one you have to answer on your own so I play baseball and I am a Highschooler so therefore two Social Groups for me would be Baseball, and Highschool

I hope this helps :)